Materials Literature
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The electronic structure of carbon overlayers on Ni(111) has been investigated by using photoemission, energy-loss, and ionization-loss spectroscopy techniques. The combined use of these spectroscopies gives a detailed picture of these surfaces which have important catalytic implications. The carbidic carbon overlayer…
A model, based on the Sm-Co system between SmCo5 (1:5) and Sm2Co17 (2:17 R and 2:17 H), is proposed to describe the metallurgical behavior of Sm(Co,Fe,Cu,Zr)z alloys between 6.8<z<8.5 in the development of hard magnetic properties. The same phases are encountered in both the binary and multicomponent all…
We have calculated the electronic structure of PtMnSb in order to explain the very high magneto-optical Kerr effect (over 2.5° at 720 nm at room-temperature) of this compound. It is shown that this behavior is related to the unusual electronic properties of PtMnSb: it is a half-metallic ferromagnet like NiMnSb. The ex…
A mathematical theory of hysteresis in ferromagnetic materials is presented based on existing ideas of domain wall motion and domain rotation. Hysteresis is shown to occur as a result of impedances to changes of magnetization such as when domain walls are pinned, while the mutual interactions of the magnetic moments a…
Carbon films were prepared by ion-beam as well as rf-discharge deposition, and annealed at temperatures up to 950\ifmmode^\circ\else\textdegree\fi{}C. Raman spectra of these films, in the range 1000-1800 ${\mathrm{cm}}^{\ensuremath{-}1}$, were analyzed via a best fit to computer-generated line shapes, used to simulate…
We report the properties of a new class of high-performance permanent magnets prepared from Nd-Fe-B and Pr-Fe-B alloys. Magnetic hardening is achieved by rapid solidification. Energy products of these isotropic materials can exceed 14 MGOe with intrinsic coercivities of ∼15 kOe. X-ray and microstructural analyses indi…
A new compound composed of Nd, Fe, and a small quantity of B (about 1 wt. %) has been found, which has a tetragonal structure with lattice constants a=0.880 nm and c=1.221 nm. This phase, which has the approximate composition, 12 at. % Nd, 6 at. % B and balance Fe, possesses remarkable magnetic properties. From the ap…
Measurements of DC electrical conductivity and ESR were made on 35TeO 2 -(65-x)V 2 O 5 -xFe 2 O 3 (mol%) glasses. They suggest that when x is changed from 0 to 1, the conductivity increases due to a decrease in effective electron hopping distance between the transition metal ions. When x is increased to greater than u…
Abstract Extreme Farbtonunterschiede bei Perylen‐3,4:9,10‐bis(dicarboximid)‐Pigmenten lassen sich durch eine geometrische Betrachtungsweise der Ergebnisse von Kristallstrukturuntersuchungen deuten. Die bei den meisten N , N ′‐Dialkylperylen‐3,4:9,10‐bis(dicarboximiden) angetroffene parallele Anordnung benachbarter Mol…
Several water-soluble paramagnetic metalloporphyrins were found to increase significantly the relaxation rate (1/T1) of water. Such compounds are known to be selectively retained by tumors in animals, and consequently we identify them as potential contrast agents for tumors in NMR imaging.
The thermal conductivity and specific heat from 0.1 to 100K and the inelastic neutron scattering spectrum has been measured for an epoxy resin Araldite MY 750 which has been hardened with primary diamines. These have the form H 2 N(CH 2 ) n NH 2 and specimens were made with n=2, 3, 4 and 12. The specific heat results…
The ESR of the first 5d ion (5d5 in a strong cubic crystal field) identified in SrTiO3, Ir4+, is observed at g approximately=1.6 with a slight temperature-dependent tetragonal anisotropy. Due to high covalency, the orbital reduction factor is rather small: k=0.5 to 0.7, meaning that the amplitude of the wavefunction i…
Several radioactive iodine isotopes arise from the production of electricity by nuclear power. Most of these are short-lived with half-lives less than a few days and will have decayed to negligible levels by the time the spent nuclear fuel is reprocessed; however, 129 I has a half life of 16 million years. Table I pre…
Abstract The response of the screw dislocation core in a body-centred cubic model lattice to a general applied stress tensor is examined by means of computer simulation. The Peierls stress is found to have the symmetry required by Neumann’s principle but is found also to have a very strong dependence on shear componen…
Abstract The change in core structure of the screw dislocation in a body-centred cubic lattice subjected to a general applied stress tensor is studied by means of computer simulation. The large variations observed are found not to be correlated with the applied stress, in that the same deformed core structure can be r…
For many years iron has become less and less important for permanent magnets. Recently, however, Japanese and American researchers have brought back iron in a new compound which produces, perhaps, the best magnetic properties ever. The largest potential for this product is electric motors, which could have half the si…
Vesicles formed from dialkyl surfactants containing vinyl, methacrylate, diacetylene, isocyano, and styrene groups have been stabilized by polymerization across their bilayers of head groups. Polymerized vesicles have shelf lives of many months and controllable permeabilities and sizes. The kinetics of surfactant vesi…
The net rate of production of ammonia from hydrogen and nitrogen synthesized by a promoted iron catalyst has been analyzed for the case of pulsed healing. Explicit expressions have been derived for the rate of production at various stages of the process. It has been shown that pulsed heating for this reaction under ce…
This paper briefly describes the preparation of amorphous films of WO3-x ·yH2O. The films were coloured either photo- or thermo-chromically, and the electrical conductivity and thermopower were measured in the temperature range 100 to 500 K. The conductivity [sgrave] could be described by the relationship [sgrave] = […
A Moraxella strain capable of utilizing 1,4-type polybutadiene as a sole source of carbon was isolated from soil. About 40% of polybutadiene having a number average molecular weight (Mn) of 2,350 was degraded and assimilated by the strain in 5 days. A polybutadiene sample with an Mn of 16,100, however, was hardly degr…